[PATCH 7/9] drm/virtio: Annotate struct virtio_gpu_object_array with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct virtio_gpu_object_array.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: David Airlie <airlied@xxxxxxxxxx>
Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Cc: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx>
Cc: Chia-I Wu <olvaffe@xxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 8513b671f871..96365a772f77 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -119,7 +119,7 @@ struct virtio_gpu_object_array {
 	struct ww_acquire_ctx ticket;
 	struct list_head next;
 	u32 nents, total;
-	struct drm_gem_object *objs[];
+	struct drm_gem_object *objs[] __counted_by(total);
 };
 
 struct virtio_gpu_vbuffer;
-- 
2.34.1